Exit times for some processes with normally distributed noise

Denna avhandling handlar om metoder för att hitta begränsningar för det asymptotiska beteendet hos en förväntad uthoppstid från ett område omkring en xpunkt för processer som har normalfördelad störning. I huvudsak behandlas olika typer av autoregressiva processer. Fyra olika metoder används. En metod som använder principen för stora avvikelser samt en metod som jämför uthoppstiden med en återkomsttid ger övre begränsningar för den förväntade uthoppstiden. En martingalmetod och en metod för normalfördelade stokastiska variabler ger undre begränsningar. Metoderna har alla både förtjänster och nackdelar. Genom att kombinera de olika metoderna får man de bästa resultaten. Vi får fram gränsvärdet för det asymptotiska beteendet hos en uthoppstid för den multivariata autoregressiva processen, samt motsvarande gränsvärde för den univariata autoregressiva processen av ordning n.

Glutamatergic transmission in the nucleus tractus solitarii: from server to peripherals in the cardiovascular information superhighway

Afferent nerves carrying signals from mechanoreceptors in the aortic arch and carotid sinus terminate predominantly in the nucleus tractus solitarii (NTS). Signal transduction and neurotransmission in the NTS are critical for central cardiovascular reflex control, but little was known about either until the late 1970's. None of the numerous neuroactive chemicals found in the NTS had met strict criteria as a neurotransmitter in the baroreflex arc until data suggested that the excitatory amino acid L-glutamate (GLU) might be released from baroreceptor afferent terminals in the NTS. In anesthetized animals microinjection into the NTS of GLU, which can be demonstrated in terminals in the NTS, produces cardiovascular responses like those seen with activation of the baroreceptor reflex. Similar responses occur in awake animals if the chemoreceptor reflex is eliminated; otherwise, in conscious animals responses mimic those of chemoreceptor reflex activation. GLU is released in the NTS upon selective activation of the baroreceptor, and possibly the chemoreceptor, reflex. Responses to selective agonists as well as baroreflex responses are eliminated by GLU antagonists microinjected into the NTS. Non-NMDA (N-methyl-D-aspartic acid) receptors seem to predominate at primary baroreceptor synapses in the NTS while NMDA receptors may be involved at later synapses. Although inhibition of soluble guanylate cyclase attenuates responses to ionotropic glutamate agonists in the NTS, nitric oxide does not seem to play a role in glutamate transmission in the NTS. GLU may also participate in transmission at cardiovascular neurons beyond the NTS. For example, a role has been suggested for GLU in the ventrolateral medulla and spinal cord. Work continues concerning GLU signal transduction and mechanisms that modulate that transduction both at the NTS and at other cardiovascular nuclei

On Distributed Storage Codes

Distributed storage systems are studied. The interest in such system has become relatively wide due to the increasing amount of information needed to be stored in data centers or different kinds of cloud systems. There are many kinds of solutions for storing the information into distributed devices regarding the needs of the system designer. This thesis studies the questions of designing such storage systems and also fundamental limits of such systems. Namely, the subjects of interest of this thesis include heterogeneous distributed storage systems, distributed storage systems with the exact repair property, and locally repairable codes. For distributed storage systems with either functional or exact repair, capacity results are proved. In the case of locally repairable codes, the minimum distance is studied. Constructions for exact-repairing codes between minimum bandwidth regeneration (MBR) and minimum storage regeneration (MSR) points are given. These codes exceed the time-sharing line of the extremal points in many cases. Other properties of exact-regenerating codes are also studied. For the heterogeneous setup, the main result is that the capacity of such systems is always smaller than or equal to the capacity of a homogeneous system with symmetric repair with average node size and average repair bandwidth. A randomized construction for a locally repairable code with good minimum distance is given. It is shown that a random linear code of certain natural type has a good minimum distance with high probability. Other properties of locally repairable codes are also studied.

Load balancing in P2P smartphone based distributed IoT systems

With the new age of Internet of Things (IoT), object of everyday such as mobile smart devices start to be equipped with cheap sensors and low energy wireless communication capability. Nowadays mobile smart devices (phones, tablets) have become an ubiquitous device with everyone having access to at least one device. There is an opportunity to build innovative applications and services by exploiting these devices’ untapped rechargeable energy, sensing and processing capabilities. In this thesis, we propose, develop, implement and evaluate LoadIoT a peer-to-peer load balancing scheme that can distribute tasks among plethora of mobile smart devices in the IoT world. We develop and demonstrate an android-based proof of concept load-balancing application. We also present a model of the system which is used to validate the efficiency of the load balancing approach under varying application scenarios. Load balancing concepts can be apply to IoT scenario linked to smart devices. It is able to reduce the traffic send to the Cloud and the energy consumption of the devices. The data acquired from the experimental outcomes enable us to determine the feasibility and cost-effectiveness of a load balanced P2P smart phone-based applications.

Formal development of resilient distributed systems

Resilience is the property of a system to remain trustworthy despite changes. Changes of a different nature, whether due to failures of system components or varying operational conditions, significantly increase the complexity of system development. Therefore, advanced development technologies are required to build robust and flexible system architectures capable of adapting to such changes. Moreover, powerful quantitative techniques are needed to assess the impact of these changes on various system characteristics. Architectural flexibility is achieved by embedding into the system design the mechanisms for identifying changes and reacting on them. Hence a resilient system should have both advanced monitoring and error detection capabilities to recognise changes as well as sophisticated reconfiguration mechanisms to adapt to them. The aim of such reconfiguration is to ensure that the system stays operational, i.e., remains capable of achieving its goals. Design, verification and assessment of the system reconfiguration mechanisms is a challenging and error prone engineering task. In this thesis, we propose and validate a formal framework for development and assessment of resilient systems. Such a framework provides us with the means to specify and verify complex component interactions, model their cooperative behaviour in achieving system goals, and analyse the chosen reconfiguration strategies. Due to the variety of properties to be analysed, such a framework should have an integrated nature. To ensure the system functional correctness, it should rely on formal modelling and verification, while, to assess the impact of changes on such properties as performance and reliability, it should be combined with quantitative analysis. To ensure scalability of the proposed framework, we choose Event-B as the basis for reasoning about functional correctness. Event-B is a statebased formal approach that promotes the correct-by-construction development paradigm and formal verification by theorem proving. Event-B has a mature industrial-strength tool support { the Rodin platform. Proof-based verification as well as the reliance on abstraction and decomposition adopted in Event-B provides the designers with a powerful support for the development of complex systems. Moreover, the top-down system development by refinement allows the developers to explicitly express and verify critical system-level properties. Besides ensuring functional correctness, to achieve resilience we also need to analyse a number of non-functional characteristics, such as reliability and performance. Therefore, in this thesis we also demonstrate how formal development in Event-B can be combined with quantitative analysis. Namely, we experiment with integration of such techniques as probabilistic model checking in PRISM and discrete-event simulation in SimPy with formal development in Event-B. Such an integration allows us to assess how changes and di erent recon guration strategies a ect the overall system resilience. The approach proposed in this thesis is validated by a number of case studies from such areas as robotics, space, healthcare and cloud domain.

Heat Demand Forecasting Models’ Development: Use of Data Mining Tools in SQL Server Analysis Services

This thesis introduces heat demand forecasting models which are generated by using data mining algorithms. The forecast spans one full day and this forecast can be used in regulating heat consumption of buildings. For training the data mining models, two years of heat consumption data from a case building and weather measurement data from Finnish Meteorological Institute are used. The thesis utilizes Microsoft SQL Server Analysis Services data mining tools in generating the data mining models and CRISP-DM process framework to implement the research. Results show that the built models can predict heat demand at best with mean average percentage errors of 3.8% for 24-h profile and 5.9% for full day. A deployment model for integrating the generated data mining models into an existing building energy management system is also discussed.

A software engineering approach to distributed systems for composite modeling

The goal of this thesis is to define and validate a software engineering approach for the development of a distributed system for the modeling of composite materials, based on the analysis of various existing software development methods. We reviewed the main features of: (1) software engineering methodologies; (2) distributed system characteristics and their effect on software development; (3) composite materials modeling activities and the requirements for the software development. Using the design science as a research methodology, the distributed system for creating models of composite materials is created and evaluated. Empirical experiments which we conducted showed good convergence of modeled and real processes. During the study, we paid attention to the matter of complexity and importance of distributed system and a deep understanding of modern software engineering methods and tools.

Distributed energy resources in an electricity retailer’s short-term profit optimization

Liberalization of electricity markets has resulted in a competed Nordic electricity market, in which electricity retailers play a key role as electricity suppliers, market intermediaries, and service providers. Although these roles may remain unchanged in the near future, the retailers’ operation may change fundamentally as a result of the emerging smart grid environment. Especially the increasing amount of distributed energy resources (DER), and improving opportunities for their control, are reshaping the operating environment of the retailers. This requires that the retailers’ operation models are developed to match the operating environment, in which the active use of DER plays a major role. Electricity retailers have a clientele, and they operate actively in the electricity markets, which makes them a natural market party to offer new services for end-users aiming at an efficient and market-based use of DER. From the retailer’s point of view, the active use of DER can provide means to adapt the operation to meet the challenges posed by the smart grid environment, and to pursue the ultimate objective of the retailer, which is to maximize the profit of operation. This doctoral dissertation introduces a methodology for the comprehensive use of DER in an electricity retailer’s short-term profit optimization that covers operation in a variety of marketplaces including day-ahead, intra-day, and reserve markets. The analysis results provide data of the key profit-making opportunities and the risks associated with different types of DER use. Therefore, the methodology may serve as an efficient tool for an experienced operator in the planning of the optimal market-based DER use. The key contributions of this doctoral dissertation lie in the analysis and development of the model that allows the retailer to benefit from profit-making opportunities brought by the use of DER in different marketplaces, but also to manage the major risks involved in the active use of DER. In addition, the dissertation introduces an analysis of the economic potential of DER control actions in different marketplaces including the day-ahead Elspot market, balancing power market, and the hourly market of Frequency Containment Reserve for Disturbances (FCR-D).

A Study of Privacy Preserving Queries with Bloom Filters

This thesis focuses on the private membership test (PMT) problem and presents three single server protocols to resolve this problem. In the presented solutions, a client can perform an inclusion test for some record x in a server's database, without revealing his record. Moreover after executing the protocols, the contents of server's database remain secret. In each of these solutions, a different cryptographic protocol is utilized to construct a privacy preserving variant of Bloom filter. The three suggested solutions are slightly different from each other, from privacy perspective and also from complexity point of view. Therefore, their use cases are different and it is impossible to choose one that is clearly the best between all three. We present the software developments of the three protocols by utilizing various pseudocodes. The performance of our implementation is measured based on a real case scenario. This thesis is a spin-off from the Academy of Finland research project "Cloud Security Services".

Organisational purchasing of service design – Agency and client perspectives

There has been an increase in the interest in service design, as companies have become more customer-centric and their focus has shifted to customer experiences. The actual organisational purchasing of service design has been given little attention, until recent years. The purpose of this study is to explore the purchasing of service design from the perspectives of sellers (service design agencies) and buying clients (business organisations). In order to understand the phenomenon, also agencies and clients’ approaches to service design discipline, purchasing processes, challenges related to purchasing and ways of facilitating the purchasing are explored. The research follows qualitative research method and utilises abductive reasoning. A proposition framework was formed by combining services marketing, design and organisational buying behaviour literatures, and was tested against real-life business cases. Empirical data was gathered by interviewing eight service design agency representatives and five client representatives in Finland. The results of semi-structural interviews were analysed by finding repetitive themes. The proposition framework was updated according to interview findings. There were both similarities and differences in service design agencies and clients’ approaches to service design. Service design represents a strategic activity to both parties, and it helps in clients’ business development and in discovering opportunities. It is an ideology; a way of thinking and working. The driving force for purchasing service design seemed to be something else than service design itself. Projects have been bought for 1) change and innovation related development, 2) channel related development or for 3) customer experience related development. Seven purchasing challenge themes were recognised: 1) poor or differing service design understanding, 2) selling of service design, 3) varying expectations, 4) difficulty of pre-evaluation, 5) buyers and buying companies, 6) project process and nature and 7) unclear project results. These all can be considered to cause challenges in organisational service design purchasing. Challenges can be caused by either participant, the agency or the client, and take place at any point of the purchasing process. Some of the challenges could be considered as barriers to purchasing or they play a role in an unsuccessful service project – and therefore, result in an unsuccessful organisational purchase. Purchasing could be facilitated in various ways by either participant; some ways are more attitude based, others actionable improvements. Thesis’s theoretical and managerial findings can be utilised to both improve the selling and purchasing of service design services.

Invoice-kaupan edut ja haitat verrattuna tavalliseen Tax Free kauppaan

Kandidaatintutkielmani käsittelee Invoice-kauppaa ja sitä, mitä etuja siihen liittyy verrattuna tavanomaiseen tax-free kauppaan. Invoice-veronpalautusjärjestelmässä EU:n ulkopuolella asuva asiakas saa veronpalautuksen samasta liikkeestä seuraavalla asiointikerralla. Arvonlisäveronpalautukset on kuitenkin haettava puolen vuoden sisällä ostosten tekemisestä. Tavanomaisessa tax-free kaupassa asiakas saa arvonlisäveronpalautuksen rajalta poistuessaan Suomesta. Invoicea käytettäessä asiakas saa verosta isomman osan takaisin kuin tavanomaisessa tax-free kaupassa, mutta palautuksen saaminen kestää kauemmin, koska Invoicea käytettäessä veronpalautuksen voi saada vain samasta liikkeestä, missä ostokset on tehty. Tutkielmani tarkastelee aihetta kauppiaan näkökulmasta. Kauppiaan kannalta Invoicen etuna on erityisesti asiakkaiden ”koukuttaminen”, koska veronpalautukset on aina haettava samasta liikkestä, mistä tuotteet on ostettu. Näin samat asiakkaat tulevat usein samaan liikkeeseen myös seuraavilla Suomen matkoilla saadakseen veronpalautukset. Tämä tuo liikkeille usein myös uusia kanta-asiakkaita.Toisaalta on huomioitava myös Invoicen käytöstä kauppiaalle ja kassoille mahdollisesti aiheutuva lisätyö ja kustannukset. Veronpalautusten maksaminen takaisin asiakkaille ja tullissa leimattujen kuittien käsittely vie kassoilla tavanomaista enemmän aikaa ja saattaa vaatia lisää henkilökuntaa. Tutkielma on toteutettu laadullisena eli kvalitatiivisena ja tutkimusmenetelmänä on käytetty haastatteluita. Haastateltavat ovat kauppiaita Kaakkois-Suomen alueelta. Tavoitteenani oli koota mahdollisimman monipuolinen haastateltavien joukko sisältäen niin vaate- ja vapaa-ajan liikkeitä kuin sekatavara- ja päivittäistavarakauppoja. Teorialähteinä käytin yliopiston kirjastosta lainattuja kirjoja, LUT:in tietokantojen ja Edilex-tietokannan artikkeleita sekä Verohallinnon dokumentteja ja verkkojulkaisuja. Lisäksi olen hyödyntänyt tutkielmassani myös ajankohtaisia uutisia sekä erilaisten paikallis- ja aikakauslehtien artikkeleita. Tutkielmani johtopäätöksissä tulin siihen tulokseen, että kauppiaan kannalta edullisinta on käyttää samanaikaisesti sekä Invoicea että perinteistä, palautusliikeiden palveluja hyödyntävää tax-free järjestelmää. Tämä mahdollistaa liikkeille mahdollisimman laajan asiakasjoukon. Suomessa usein käyvät ostosmatkailijat suosivat yleensä Invoicea täysimääräisen veronpalautuksen vuoksi. Palautusliikkeet taas veloittavat asiakkaalle maksettavasta veronpalautuksesta oman palvelumaksunsa. Suomessa harvemmin vieraileville taas palautusliikkeiden palvelut ovat edullisempia, sillä veronpalautukset saa rajalta maasta poistuttaessa, eikä tarvitse palata samaan liikkeeseen puolen vuoden sisällä. Palautusliikkeiden etuna Invoiceen nähden on myös asioinnin vaivattomuus, sillä eri liikkeissä asioivat ostosmatkailijat saavat kaikista matkalla tekemistään ostoksista arvonlisäveronpalautuksensa yhdestä paikasta sen sijaan, että kävisivät hakemassa ne joka liikkeestä erikseen.

Globe & Mail clipping announces V&B's new client

This Januayr 19, 1979 clipping from the Globe & Mail announced the successful outcome of the pitch made for the McDonald's Restaurants Ltd. account.